Abstract: According to proton radiography concepts of the Los Alamos National Laboratory, the expressions of areal density in high-energy proton radiography are obtained by studying the high-energy protons interactions with materials. The areal density uncertainty and the position resolution are analyzed. Compared with high-energy X-ray radiography, the detection of edges and density reconstruction for a thick object are more accurate as the transmitted flux of protons is increased. The effects of the multiple coulomb scattering and chromatic aberrations in the magnetic lenses on the spatial resolution are studied. It is shown that high-energy proton radiography is superior to high-energy X-ray radiography in penetrating power, areal density measurement, material composition identification and posit